SURGICAL INFECTION AND ANTIBIOTICS OUTLINE Introduction and overview Definitions and SIRS Risk...

SURGICAL INFECTION AND ANTIBIOTICS

OUTLINE Introduction and overview Definitions and SIRS Risk factors for surgical infections Strategies for infection prevention Peritonitis and intraabdominal abscess Special infections Infection risk for the surgeon


Infection

The inflammatory response to the presence of microorganisms


Sepsis

The systemic inflammatory response syndrome in response to infection


Severe Sepsis

Sepsis associated with organ dysfunction, hypoperfusion or hypotension


Septic Shock

Sepsis with hypotension, despite adequate fluid resuscitation, along with the presence of perfusion abnormalities that may include, but are not limited to, lactic acidosis, oliguria, or an acute alteration in mental state


The Systemic Inflammatory Response Syndrome Caused by the systemic effects of locally released cytokines Cytokine release can be triggered by both infectious and

noninfectious insults Provides a conceptual framework for the understanding of

ARDS and MODS in the absence of infection


Systemic Inflammatory Response Syndrome

Manifested by two or more of the following: Temperature > 38 C or < 36 C Heart rate >90 Respiratory rate > 20 or PCO2 <32 WBC > 12 K < 4K or > 10% bands


Multiple Organ Dysfunction Syndrome

The presence of altered organ function in an acutely ill patient such that homeostasis cannot be maintained without intervention


Risk Factors for Surgical InfectionSurgical wound classSENIC projectNNISS


Surgical Wound Class

Developed by National Research Council in 1964 Classifies wounds into one of four classes based on degree

of contamination– Clean– Clean contaminated– Contaminated– Dirty


Study on the Efficacy of Nosocomial Infection Control Published by Haley in 1985 Utilizes four risk factors to stratify risk

Abdominal operationOperation longer than 2 hoursContaminated or dirty wound classHaving 3 or more medical diagnoses


National Nosocomial Infection Surveillance System

Developed by Centers for Disease Control Uses 3 risk factors

ASA score of 3 or greater

Operation classed as contaminated or dirty

Operation of longer than “T” hours with “T” being operation specific


Antibiotic prophylaxisMust be given pre-incisionNo justification for additional dosingAppropriate pharmacokineticsBenefits outweigh risks


Peritonitis and Intraabdominal Abscess

Conventional Principles of Management Control source of contamination Irrigation of peritoneum with saline Closure of the abdomen Close monitoring


Peritonitis and Intraabdominal AbscessAntibiotic Therapy

Usually empiric Rarely altered by culture data Should include anaerobic coverage


Peritonitis and Intraabdominal AbscessDuration of Antibiotic Therapy

Often empiric e.g. 5,7,10 or 14 days Often unnecessarily prolonged Usually not based on clinical parameters

SURGICAL INFECTION AND ANTIBIOTIC

Peritonitis and Intraabdominal AbscessDuration of Therapy

Patients who are afebrile and with normal WBC’s rarely develop further infection if antibiotics are stopped

Approximately 30% of patients who are afebrile but with leukocytosis develop further infection when antibiotics are stopped

Approximately 80% of patients who are still febrile at the conclusion of antibiotics will develop further infection


Peritonitis and Intraabdominal Abscess

Duration of Therapy

Summary Afebrile patients with normal WBC-stop antibiotics Afebrile patients with leukocytosis-either continue antibiotics or evaluate

for residual infection Febrile patients-evaluate for residual infection


Special Infections Fungal infections Diabetic foot infections Hand infections Invasive streptococcal infections C. dificile infection Tetanus


Fungal Infection Fungal colonization common in ICU Fungal infection less common Risk factors for fungal infection

Severity of illness (APACHE 20 or >)

Intensity of colonization


Fungal Infection Diagnosis depends on high index of suspicion Careful culture of blood, urine, sputum, and drain

material Eye examination important


Fungal Infection

Therapy Amphotericin B 0.5 mg/kg/day IV for 7-10 days Fluconazole 400 mg/day po for additional 7 days Remove central venous catheters


Diabetic Foot Infection

Risk Factors for Foot ProblemsNeuropathyVascular insufficiencyAltered response to infection


Diabetic Foot Infections

Role of Antibiotics Antibiotic therapy is an adjunct to overall surgical care Most infections polymicrobial 90% are gram + organisms 50% are gram - organisms 50% are anaerobes


Hand Infections Commonly seen ER condition 60% trauma 30% human bites 10% animal bites Most infections result from neglected injury Antibiotics given early prevent many complications Reaction to infection determined by anatomic compartments of hand


Microbiology of Hand Infections Microbiology depends on type of injury Staph aureus in 35% Anaerobes in 35% 50% of human bites infections are predominantly

anaerobic


Antibiotics in Hand Infections

Coverage should be directed by culture data In the absence of culture material use broad spectrum

penicillin plus B-lactamase inhibitor (e.g. amoxicillin/clavunanate)

Erythromycin a good alternative in penicillin allergic patients


Hand Infections Management Principles

Immobilization Splinting Rest Elevation Surgical drainage Appropriate antibiotics


Invasive Streptococcal Infections Include puerperal sepsis, scarlatina maligna, septic scarlet

fever, bacteremia, erysipelas, necrotizing soft tissue and fascia infection, gangrene, and myositis

Recent increase in the number and virulence of these infections

Occur mainly in healthy, immunocompetent patients


Necrotizing Soft Tissue and Fascial Infection

First described by Meleney in 1924 Preantibiotic era mortality rate 20% Modern era mortality rate 50% Increase in virulence? Decrease in specific immunity?


Necrotizing Soft Tissue and Fascial InfectionPresentation

80% follow minor trauma 20% post operative Initial lesion frequently mild erythema Swelling, heat, erythema occur rapidly and spread from

initial lesion Systemic toxicity early and severe



Microbiology Group A hemolytic strep Staph Aureus Enteric organisms including Clostridia species



Treatment Aggressive surgical debridement Initial empiric antibiotic coverage for Staph, Strep, Enterics

including Clostridia Tailor antibiotic coverage to culture results


Clostridium Dificile Associated Diarrhea Most common cause of nosocomial diarrhea on surgical

units Variable manifestations including

– No symptoms– Peritonitis, toxic megacolon, perforation, death


Clostridium Dificile Associated Diarrhea Clinical Criteria for Diagnosis

3 or more loose stools per day for >2 days without an obvious cause

Previous antibiotic or antineoplastic administration within 6 weeks

Response of the diarrhea to oral vancomycin or metronidazole


Clostridium Dificile Associated Diarrhea

Laboratory Criteria for Diagnosis C. dificile culture-most sensitive test C. dificile toxin assay-most specific test Clinical diagnosis plus positive culture adequate to

confirm diagnosis


Clostridium Dificile Associated DiarrheaEndoscopic Diagnosis

Scope optionsRigid proctosigmoidoscope (25 cm)Flexible sigmoidoscope (60 cm)Colonoscopy

If patients do not have pseudomembranes on limited exam, then colonoscopy indicated

Lack of pseudomembranes DO NOT rule out disease


Clostridium Dificile Associated Diarrhea

Severe Disease Uncommon (0.39% of patients with CDAD) Indications for operation

Signs of peritonitis

Signs of organ failure

Worsening CT findings Surgical procedure of choice-Total abdominal colectomy with ileostomy Mortality rate 36%


TetanusPreventable disease 100 new cases reported per year in USA


Tetanus Prophylaxis Guidelines

ACS Committee on Trauma

General Principles Guidelines for both general and specific preventive measures are available Prevention depends upon

Adequate immunization of general population

Good surgical wound care

Passive immunization with tetanus immune globulin-human as indicated


Infection Risk for the Surgeon HIV Hepatitis B Hepatitis C


HIV Risk of infection relatively low (0.3-0.1%) Universal precautions for all cases Additional precautions in known or strongly

suspected cases


HIV Postexposure Prophylaxis

Recommended for exposure to known HIV infected patients or high risk patients

Therapy within 1-2 hours postexposure and continued for 4 weeks

2 drug therapy in all cases, 3 drug for “high risk” exposure Drugs: zidovudine, lamivudine, and indinavir


HIV No clearly documented case of surgeon to patient

transmission reported Universal precautions important No justification for restriction of HIV+ surgeon’s

privileges


Hepatitis 12,000 infections with 250 deaths in HCWs per

year Much more dangerous than HIV Cases equally divided between B & C


Hepatitis

Prevention Vaccination for hepatitis B Universal precautions


Hepatitis

Transmission by Surgeons Transmission documented in 18 cases All HBe Ag positive Risk if HBe Ag negative is very low


Questions?

SURGICAL INFECTION AND ANTIBIOTICS OUTLINE Introduction and overview Definitions and SIRS Risk...

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